Optimization of III–V compound semiconductor heterostructures for distributed Bragg reflector applications in VCSELs

A selectively oxidized vertical cavity surface emitting laser (VCSEL) has been designed and fabricated for operation at a wavelength of 1.546 μm. The device structure was grown on an InP substrate using III–V quaternary semiconductor alloys for the two mirror stacks and unstrained multi-quantum wells for the active layer. A threshold current as low as 2.2 mA has been achieved. The influence of the intentional and growth-related compositional grading at the heterointerfaces on the mirror reflectivity and laser characteristics has been investigated, and key sensitivities to laser performance have been determined.